Lecture 2 Macromolecules Carbohydrates. Thanks, Water!

Lecture 2

MacromoleculesCarbohydrates

Thanks, Water!

Yesterday’s Exit Ticket:

OH

H Shared Electrons

Covalent Bond

Covalent Bond

Hydrogen Bond

OH

H Shared Electrons

Covalent Bond

Covalent Bond

https://www.youtube.com/watch?v=QqjcCvzWwww

The polarity of water molecules, and the resulting hydrogen bonds among molecules,give water properties that support life on Earth

• Cohesion• Temperature moderation• Solvent of life• ??

Key Themes(2) “Think Like a Biologist”: Understand What Life Is.

“Unity” of life: What are the common features of all life?

• Structure and function of the molecules of life

Organic vs. Inorganic

• ORGANIC COMPOUNDS: – Biologically-derived– Contain carbon (C) and

often hydrogen (H)– Involve covalent bonds

• INORGANIC COMPOUNDS:– Not biologically-derived– Feature ionic bonds

?

Blogs.scientificamerican.com; demotix.com

BIOLOGY CRASH COURSE:(Because I can only talk so much…)

http://www.youtube.com/watch?v=QnQe0xW_JY4&list=EC3EED4C1D684D3ADF

Another one on water and bonds:

http://www.youtube.com/watch?v=HVT3Y3_gHGg

(1:54-5:07)

Most macromolecules are polymers, built from monomers

• Three of the four classes of life’s organic molecules are polymers:– Carbohydrates– Proteins– Nucleic acids

• A polymer is a long molecule consisting of many similar building blocks

• These small building-block molecules are called monomers

Copyright © 2008 Pearson Education, Inc., publishing as Pearson Benjamin Cummings; provocraft.com

Biologically Important Macromolecules

1. Carbohydrates (made from simple sugars)

(large molecules constructed from simpler molecules)

2. Lipids (from fatty acids)

4. Proteins (from amino acids)3. Nucleic acids (from nucleotides)

Fig. 4.1: Life is based on carbon

The polarity of water molecules, and the resulting hydrogen bonds among molecules,give water properties that support life on Earth

• Cohesion• Temperature moderation• Solvent of life• Macromolecule creation and breakdown

All macromolecules are formed from small building blocks strung together by removing water:

-H from one end and

-OH from the other

Synthesis (formation) of macromolecules

HO H1 2 3 H HO

H2OFig. 5.2 (a)

Fig. 5.2 (a)

Synthesis (formation) of macromolecules

Single unit = monomer; macromolecules with many monomers = polymers

Dehydration removes a watermolecule, forming a new bond

Short polymer Unlinked monomer

Longer polymer

HO

HO H

H1 2 3

1 2 3 4

H HO

H2O

Dehydration synthesis

Macromolecules are broken down by adding water (hydrolysis).

Breakdown (digestion) of macromolecules

Fig. 5.2 (b)

Hydrolysis adds a watermolecule, breaking a bond

HO H

HHO H HO

H2O

1 2 3 4

321

Synthesis and Breakdown of Macromolecules

http://www.colorado.edu/ebio/genbio/05_02Polymers_A.html

Today’s Exit Ticket• Make a chart listing the 4 types of biological

molecules, their monomers, and their functions

Macromolecule Monomer or Types

Function(s) Key Element(s) (e.g. carbon)

Carbohydrates

healthtips-sastha.blogspot.com

• Carbohydrates are sugars and their polymers– Monomer: monosaccharides (single sugars)– Macromolecules: disaccharides & polysaccharides– Key elements:

• C, H, O

• Lipids do not form polymers• The unifying feature of lipids is having little or

no affinity for water (hydrophobic)• Key elements: C, H• Biologically important lipids:

– Fats– Phospholipids– Steroids

Lipids

Recipes.wiki.com; pictureschat.com;

• Fats: Energy storage• Phospholipids: Cell membranes• Steroids: Hormones, cholesterol

communication component of animal cell membranes, precursor for

hormones

Animals.nationalgeographic.com

Lipid Functions

Proteins– Monomer: Amino acids– Polymer: Polypeptide (aka protein)– Key Elements: C, H, N, “R” (R varies)

Copyright © 2008 Pearson Education, Inc., publishing as Pearson Benjamin Cummings

Proteins are:a) Hydrophobicb) Hydrophilicc) Could be eitherd) Not sure

Protein Functions• Proteins are >50% of the dry mass of most cells

– Structural support– Storage– Transport– Cellular communications– Movement– Defense against foreign substances– ALL enzymes are proteins – chemical reactions

wouldn’t occur in our cells without proteins!


Nucleic Acids– Monomer: Nucleotides– Polymer: Nucleic acids (DNA, RNA)– Key Elements: Sugar (C, H, O), N, Phosphate (P, O)– Functions: Stores and transmits hereditary information


Nitrogenousbase

Phosphategroup Sugar

Fig. 5-27ab5' end

5'C

3'C

5'C

3'C

3' end

(a) Polynucleotide, or nucleic acid

(b) Nucleotide

Nucleoside

Nitrogenousbase

3'C

5'C

Phosphategroup Sugar

(pentose)

Fig. 5-UN2

Real World Connection:Human Health

The role of nutrition in(physical & mental) health

Functions of diet

• Energy supply• Building blocks • Regulators of metabolism

Guysandgoodhealth.com

Cellular respiration releases energy: O2 + Sugar H2O + Energy + CO2

I(H-C-OH)n

I

Sugars are “burned” for energy gain with oxygen in cellular respiration

Energy supply

Breaking C-H bonds releases energy

Photosynthesis uses solar energy to make sugars: O2 + Sugar H2O + Energy + CO2

I(H-C-OH)n

I

Building C-H bonds requires energy

Respiration

CHOH

sugar

Breaks C-H bonds(releasing a lot of energy)

Life’s major energy conversions: Light energy Chemical Energy Cellular Work

Photosynthesis

Makes C-H bonds(using the sun’s energy)

http://www.okgenweb.org/~okmcinto/Midway/classlist/1984.htm

5 minute break…

Carbohydrate macromolecules are built from simple sugars

Simple sugars generally have several of these units: I H - C - OH (CH2O)n

I

The names of carbohydrates often end in “ose”, as for hexose sugars (with 6 C) like glucose, fructose, and galactose.

Fructose

Glucose Galactose

Hexoses (C6H12O6)

Fig. 5.3

Sugars• Monosaccharides: molecular formulas in multiples of CH2O

– Glucose (C6H12O6) is a common monosaccharide

– Classified by the number of carbons in the carbon skeleton (hexose = 6 Cs)

– Major fuel for cells and as

raw material for building molecules


Glucose Fructose Sucrose

Fig. 5.5

Monosaccharides Disaccharide

Dehydration reaction (-H2O) in the synthesis of sucrose

Sugars exist as rings in the cell.

ET1

Fig. 5-5

MaltoseGlucoseGlucose

(a) Dehydration reaction in the synthesis of maltose

Disaccharides

Fig. 5-5

(b) Dehydration reaction in the synthesis of sucrose

Glucose Fructose Sucrose

MaltoseGlucoseGlucose

(a) Dehydration reaction in the synthesis of maltose

Disaccharides

A disaccharide is formed when a dehydration reaction (-H2O) joins two monosaccharides

http://www.colorado.edu/ebio/genbio/05_05Disaccharides_A.html

Important Monosaccharides

Glucose, fructose, galactose

Foodnsport.com

• Fuel for cells• Raw material for building larger

molecules

Important Disaccharides

Table sugar (transport sugar in plants) = sucrose

(1 glucose + 1 fructose)

Topnews.in; cals.ncsu.edu


Table sugar (transport sugar in plants) = sucrose

(1 glucose + 1 fructose)

Meijer.com; thenibble.com

Processing and bleaching

+ Molasses

Predict the formula for a disaccharide made from two hexoses.A) C2H4O2

B) C6H12O6

C) C12H24O12

D) C12H22O11

Deduce answer by combining pieces you already know.

Hexose has 6 carbons

I Carbohydrates have general formula of H-C-OH or (CH2O)n

C6H12O6 for a hexose I

When two hexoses are connected, one H2O molecule comes out: C6H12O6 + C6H12O6 = [C12H24O12 - H2O] = C12H22O11

Think-Pair-Share


Milk sugar = lactose (1 glucose + 1 galactose)

Farmboy24.flickr.com; thedailygreen.com

Lactose intolerance

Different from allergy to milk Role of genetic background(Nutrigenomics)

Uneeda-audio.com

Polysaccharides• Polysaccharides are the polymers of sugars

– Are more than 2 monosaccharides together– Have storage and structural roles

• Glycogen (energy storage in animals)• Starch (energy storage in plants)• Cellulose (cell wall structure in plants)• Chitin (cell wall structure in fungi; exoskeleton

structure in arthropods [insects/crustaceans])


Energy storage polysaccharides: Starch and glycogen are BOTH made from glucose

Starch

Amylose

Chloroplast

Amylopectin

Mitochondria Glycogen granules

0.5 µm

1 µm

Fig. 5.6

Starch - mostly in plants Glycogen - mostly in animals

• Chitin– Exoskeleton of arthropods– Structural support for the cell walls of many fungi


Structural Polysaccharides

Chitin forms theexoskeleton ofarthropods.

Chitin is used to makea strong and flexiblesurgical thread.

Fig. 5.9

Many organisms have enzymes that break bonds in starch.

Only a few microbes have enzymes to break bond in cellulose. Animals cannot break cellulose bond, but some - cows and termites - use microbial symbionts that can.

Cellulose makes up the tightly-packed fiber structure of plant cell walls

Glucosemonomer

Cellulosemolecules

Cellulosemicrofibrilsin a plantcell wall

0.5 µm

10 µm

Cell walls

Microfibril

Fig. 5.8

Extension.umn.eduHuman Appendix – Biological Remnant?

Functions of diet

Energy storage capacity:

Gram-for-gram, fats store twice as much energy as carbohydrates and proteins

• Carbohydrates = 4 kcal/gram (CHOH)n

• Proteins = 4 kcal/gram (CH”R”)n

• Fats = 9 kcal/gram (CH2)n

I H - C - OH

I“Carb”

I H - C - H

I Fat

Glycogen•Quickly mobilized & quickly exhausted•Good for sprint/mental tasks Fat•Slowly mobilized & more lasting•Good for extended exercise/marathon

On “Atkins Diet” (low carbohydrate diet), glycogen stores shrink and can result in “low energy”

Today’s Exit Ticket• Make a chart listing the 4 types of biological molecules,

their monomers, and their functions

• What element(s) (i.e. atom types) do all 4 molecules have in common?

Macromolecule Monomer or Types

Function(s) Key Element(s) (e.g. carbon)

Lecture 2 Macromolecules Carbohydrates. Thanks, Water!

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